Talk:Phi (disambiguation)

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Regarding Phi not being the diameter symbol. I live in Europe (specifically, Romania), I'm an engineer, and we definitely use Phi for diameters -- even in speaking, "phi 22" means "a diameter of 22 mm". The fact that the symbol may look a little different in some circumstances may be true, but since this is an encyclopedia, I was trying to document the logical rather than visual symbol usage. Didn't revert Radiojon's edit because he was basically reverting mine, so we would've ended up in a potential edit war -- could someone with a say in this decide this for us? --Gutza 22:25, 24 Aug 2003 (UTC)


 * I have a small amount of training in engineering drawing, and I know that a diameter symbol is drawn like "ø". But if you say it's pronounced "phi" then your word is good enough for me. The problem here seems to be that you both are trying to summarise a complex situation down to a single sentence. Why? -- Tim Starling 23:59, 24 Aug 2003 (UTC)

Thanks for taking the time to get involved! Not really sure why, now that you're asking... :) Probably because the topic is the Greek letter Phi, which is used in more than one context, and since I never thought the distinction between Φ and ø needed to be made, I just wrote what you can see in the article history (basically what's left now), but Radiojon's bold statement made me think twice before reverting, that's why I asked for arbitration. To cut the long story short, I have absolutely no problem with mentioning the symbol is/may/must be drawn somewhat different in some parts of the world - or even better, include some history -, just don't state "This is incorrect" so decisively. --Gutza 00:23, 25 Aug 2003 (UTC)

Me again. Tried looking for some engineering drawings, and I have to admit Radiojon is right, the representation is indeed ø over here as well, but the symbol is, again, defintely called "Phi" in speaking. Maybe someone with a little background on the topic can clear the issue? --Gutza 00:36, 25 Aug 2003 (UTC)

I promise, I wouldn't get into an edit war with anyone. :-)  I think the diameter symbol is neither Φ/φ nor Ø/ø, but a separate symbol that looks very similar to ø.  Maybe the use of phi is just a corruption of this, that has just come to be accepted?  (Maybe conversely, the diameter symbol is a corruption of phi, though I doubt this, since the ø-like symbol itself seems a very logical visual representation for diameter.)

I have included what I know to be the diameter symbol at left, which is taken from the ø in the Times Roman style font. It was modified to extend the stroke further to the upper right and not as far to the lower left, and to make the stroke thick and thin at those ends respectively. Apparently this is somewhat stylistic, to differentiate it from the letter ø, but is not yet included separately (and/or identically styled) in fonts. Unicode does list a separate diameter symbol as character hex 2300 (decimal 8960), which you would use &amp;#x2300; or &amp;#8960; to get, which in turn displays ⌀ and ⌀ in your browser. --radiojon 07:51, 2003 Aug 25 (UTC)


 * Finally, a use for my engineering drawing textbook! It is Engineering Drawing, A.W. Boundy 5th ed. I knew I had been keeping it for something. It uses a diameter symbol which is a circle roughly the height of a capital letter, with a stroke at 30&deg; from vertical. The circle and the stroke are both drawn with a thin line -- no thick or thin ends. At no stage do they call it "phi". Note that although my browser renders &phi; as a single curvy stroke, it's often written in a way similar to the symbol described above. Anyway, assuming we can't find a definitive answer on etymology, I suggest we change the article to say that the diameter symbol is often referred to as "phi". I don't think there's any need to proclaim this usage "right" or "wrong". -- Tim Starling 01:25, 26 Aug 2003 (UTC)


 * Okay, I've drawn a small version of the Boundy diameter symbol, using Word: [[image:Boundy diameter.svg]]. Sorry, I don't have a scanner. I replaced the ø in the article with the new image. -- Tim Starling 01:47, 26 Aug 2003 (UTC)